This invention relates generally to the field of underwater mine countermeasure warfare, and more particularly to an underwater mine countermeasure warfare system utilizing an air cushion vehicle equipped with a magnetic sweep generator capable of emitting a magnetic field pattern for exploding submerged mines having magnetic field responsive detonators.
It has long been well known in the field of both land and sea warfare to set mines in strategic locations which will explode at an appropriate moment to destroy vehicles and land vehicles which are within the explosive range of the mines. In addition to mere contact between a vehicle and a mine, various techniques have been developed to cause the mines to explode remotely so that the vehicle suffers damage without actually contacting the mine. For example, some mines are provided with acoustically responsive detonators which cause the mines to explode when the detonator detects a predetermined sound wave pattern which simulates the sound pattern of a ship or other vehicle. Another example is mines which are provided with magnetically responsive detonators which cause the mines to explode when the detonator detects a predetermined magnetic field pattern which simulates the magnetic field or signature of an approaching ship. Some mines require a particular orientation and time rate of change of the magnetic field, the acoustic field, or both, before they will explode.
However, with each new technological advance in the sophistication of detonating systems for mines, a countermeasure is soon developed for defeating the effectiveness of a new detonator. This is normally accomplished by devising systems which simulate the condition to which the detonator is responsive so that the mine is caused to explode harmlessly without damage to any nearby vehicles. For example, contact mines can be exploded by dragging various devices along the surface on which the mines are imbedded or floating, as the case may be, by a helicopter. Acoustic mines can be exploded by transmitting a pattern of acoustic waves which simulate the sound pattern of a vehicle or vehicle to which the detonator is responsive, such as the sound pattern emitted by the engines of a ship. Similarly, magnetic mines can be exploded by generating a magnetic field which simulates the magnetic signature of an approaching and or departing vehicle or vehicles. This technique is particularly suitable to exploding underwater mines because large ships emit a distinctive magnetic field pattern because of both the large mass of metal and a variety of equipment which generates various magnetic field patterns. Often mines are designed to explode only after being exposed to a predetermined number of exposures to the critical parameters, which can be conveniently accomplished by an automated system to repetitively generate a field simulating a target ship's approaching or departure pattern.
A major problem with any system for simulating a condition to which a mine is responsive is that of bringing the simulating system into sufficiently close proximity to the mine to cause it to explode without damaging the vehicle used to transport the simulating system. Many solutions to this problem have been put forth from time to time, such as the use of helicopters as mentioned above or slow flying airplanes dragging or towing the condition simulating equipment, and land and sea vehicles equipped with the necessary simulating equipment which can function out of range of the explosive force of the mines.
Prior to the present invention, one solution in particular worked rather effectively as an underwater mine countermeasure system, which is the type of mine warfare with which the present invention is primarily concerned. This solution included a pontoon supported vehicle which could be remotely controlled from another vehicle, and which included apparatus for generating a magnetic field in the water which extended for some considerable distance beyond the vehicle. The magnetic field was generated by a combination of a horizontal loop magnetic coil located on the railing of the vehicle in a plane parallel to the deck of the vehicle. Additionally, four more axial coils were found on two heavy iron pipe cores located in the pontoons of the vehicle. The magnetic field generated by this combination of coils was of sufficient intensity to explode submerged mines having magnetically responsive detonators while the vehicle was still out of range of the explosive force of the mine so that it suffered no damage. Unfortunately, the vehicle could travel at only a moderate speed, thereby impeding its ability to move quickly from one operational location to another; it had very limited maneuverability; and being in the water it was subject to underwater shock from exploding mines and therefore had to be operated at considerable distances from the mines, necessitating very high capacity magnetic field generating equipment.